Handle assignability for Send and SendSet

sdk/lib/_internal/compiler/implementation/compiler.dart

Index: sdk/lib/_internal/compiler/implementation/compiler.dart
diff --git a/sdk/lib/_internal/compiler/implementation/compiler.dart b/sdk/lib/_internal/compiler/implementation/compiler.dart
index c2de002e40028e6a3bcbbab4b50c7411e1f48e81..4aa311ba54c4b7429fd69b41ea85d3b0d8fd2235 100644
--- a/sdk/lib/_internal/compiler/implementation/compiler.dart
+++ b/sdk/lib/_internal/compiler/implementation/compiler.dart
@@ -1024,7 +1024,6 @@ abstract class Compiler implements DiagnosticListener {
     if (message is TypeWarning) {
       // TODO(ahe): Don't supress these warning when the type checker
       // is more complete.
-      if (identical(message.message.kind, MessageKind.NOT_ASSIGNABLE)) return;
       if (identical(message.message.kind, MessageKind.MISSING_RETURN)) return;
       if (identical(message.message.kind, MessageKind.MAYBE_MISSING_RETURN)) {
         return;